Timing device for electric current



May 18, 1943 L. R. CALVERT TIMING DEVICE FOR ELECTRIC CURRENT Filed May 25, 1940 4 Sheets-Shoat 1 INVENTOR A. la can 5E7 ATTORNEY May 18, 1943 L. R. CALVERT TIMING DEVICE FOR ELECTRIC CURRENT Filed May 25, 1940 4 Sheets-Sheet 2 IHIHF .ulHI

- iNvEN'roR LE. C/IA VE/E'T ATTO RN EY May 18, 1943 1.. R. CALVERT TIMING DEVICE FOR ELECTRIC CURRENT Filed May 25, 1940 4 Sheets-Sheet 3 INVENTOR L. 7? CfiI/EET BY mm ATTORNEY 4 Sheets-Sheet 4 May 18, 1943 L. R. CALVERT TIMING DEVICE FOR ELECTRIC CURRENT Filed May 25. 1940 ATTORNEY \NVENTOR A. R. CfiLVEiCT J k a 9 4 Patented May 18, 1943 TIMING DEVICE FOR ELECTRIC CURRENT Landon Ralls Calvert, Bloomfield, N. 1., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 25, 1940, Serial No. 337,157

18 Claims.

This invention relates to a timing device for electric current and, more particularly, to one for accurately regulating the time electric current is on within close and dependable limits.

The principal object of my invention, generally considered, is to provide aparatus for regulating the time an electric circuit is maintained, as for electric welding and other processes requiring predetermined amounts of energy.

Another object of my invention is the provision of a timing device for electric current, comprising adjustable discs or cams with high and low dwells, operated intermittently through a clutch and continuously running motor, whereby a circuit is closed when a make contact element drops from the high dwell on one contact disc, and opened when a break contact drops from the high dwell on another cam, the control of said discs being such that the circuit canno again be accidently closed.

A further object of my invention is the provision of a timing device for electric current, including a latch operated by a treadle, or other device conveniently put in motion by an operator, and connecting hook, which allows a stop bar and connected discs to rotate one revolution, or until said stop bar re-engages the latch after release by the hook.

A still further object of my invention is the provision of a timing device for an electric current, in which cam discs are employed which may be adjusted with respect to one another, and another disc or discs added to perform additional operations.

Special features of my invention are the employment of adjustable c'am discs which rotate when released, or when the clutch which causes rotation of the carrying shaft is allowed to engage, each disc being formed with high and low dwells and resiliently-pressed contact elements engaging the same, one of said elements making a contact when it drops from the high to the low dwell of its disc, and the other breaking a contact when it drops from the high to the low dwell on its disc, and a conductor putting said elements in series with a load, in order to accurately predetermine the length of time an electric current is supplied to said load, by the angular displacement between the corresponding dwells on said discs, and means for varying said displacement to vary the length of time.

Other objects and features of the invention, relating to the particular arrangement and construction of the various parts, will become apparent as the description proceeds.

Referring to the drawings illustrating my invention:

Figure 1 is a side elevational view of welding apparatus embodying my invention.

Figure 2 is a front elevational view of the apparatus of Figure 1, with parts in vertical section.

Figure 3 is a vertical sectional view on the line IIIIII of Figure 2, in the direction of the arrows.

Figure 411s a vertical sectional view on the line IV-IV of Figure 2, in the direction of the arrows, showing the timing discs in normal or inactive positions.

Figure 5 is a view corresponding to Figure 4, but showing the positions and the parts after the timing discs have moved until the make contact element has rotated clockwise and the cam engaged roller thereof dropped from the high to the low dwell on its disc, to complete the circuit.

Figure 6 is a view similar to Figure 4, but showing a position subsequent to that of Figure 5 in which the break contact element has rotated clockwise and the cam engaged roller thereof dropped from the high to the low dwell on its disc, to break the circuit.

Figure '7 is a fragmentary top plan on the line VIIVII of Figure 2.

Figure 8 is a wiring or circuit diagram of the apparatus shown in Figures 1 to "l, inclusive.

Figure 9 is mainly in side elevation, like Figure 1, and on the line IX-IX of Figure 10, showing another embodiment of my invention.

Figure 10 is a front elevational view of the apparatus illustrated in Figure 9.

Referring to the drawings in detail, and first considering the embodiment of my invention illustrated in Figures 1 to 8, inclusive, there is shown a table or bench ii on which is mounted a bracket i2, adjustably supporting the lower electrode I3 of apparatus for welding small parts, such as those forming incandescent electric lamps, radio tubes or the like.

The table it also carries a bracket I in which is journalled a shaft I5 serving to pivotally mount an arm it fixed on said shaft and carrying the upper electrode I! for cooperating with the electrode l3 in performing the desired welding operations.

The electrode H is normally held in upper position away from the electrode :13, as by means of a spring !8 acting on a rearwardly projecting arm I9 of a bell crank 20 pivoted on the shaft 7 The arm 2t also car l5, and with its lower end connected to the bracket ML A The other arm 2| of the bell crank 20, carries a flange 22 having an outer surface 23 cylindrically curved about the axis of the shaft l5. The surface 23 is normally engaged by a lug or roller 24 on an arm or crank 25, mounted on a shaft 26, Journalled in the bracket 54, and carrying a make-and-break device 27, including, for example, a mercury contact tube 28 for intermittently closing and opening a circuit through conductors 29 and 3!.

The shaft 28 is normally biased by the spring 32, acting between an arm 93 projecting therefrom and the bracket M, so that the, lug or roller 29 resiliently engages the cylindrical surface 23. es a cam device 84, pivotally mounted on a shaft 95 which projects therethrough, the other end of said shaft carrying an arm 38 from which a spring 8'! extends to a stud 38 for resiliently urging the cam device 38 into engagement with the curved surface 28.

A tension spring 39 connects the bell crank arm I9 with an arm El fixed on the shaft l5, for resiliently urging the bell crank arm 2i against a stud or lug 32 on an arm 53 fixed on the shaft l 5. Thus the electrode it is resiliently urged to its uppermost position by the spring l8 acting on the arm l9, and the arm 2!! acting on the lug 4.12 of the arm 93 to urge the shaft l5 and arm l5 carried thereby in a counterclockwise direction, as viewed in Figure 1.

A treadle 48, pivoted to a floor bracket 55, as indicated at 55, is provided, and connected to the arm 2i by a chain or the like Lil, passing over pulley 98 pivotally mounted at 69. When the operator 5!: depresses said treadle, through the angle designated by the reference character 5i, the electrode H is brought into engagement with that designated 83.

Upon further movement, or when the treadle has traversed the angle 52, the lug or roller 29 is caused to ride up on the cam device 34, and momentarily energize a solenoid 58 mounted in box 58, by turning the make-and-break device 27 sufiiciently, by a corresponding movement of its shaft 26, that the mercury contact tube 28 is tilted, closing the solenoid circuit through the conductors 29 and 3!.

Upon still further movement, the lug 24 drops ofi the hub of the device 84, opening the solenoid circuit. When the treadle has traversed the angle 55, the circuit is still open.

All this movement is accomplished by the crank arm l9 resiliently operating the arm t! through the spring 99, to move the arm l6 and electrode I7, by means of the shaft l5 to which the parts are fixed. When the electrode ll engages the cooperating electrode it, further movement of the arm it merely places the spring 39 under greater tension, and causes said arm to depart from engagement with the lug 42. Upon release of the treadle M, the parts return to initial positions, the lug 28 moving back between the curved surface 23 and the cam device 84 against the action of the spring 37, without again closing the solenoid circuit.

Beneath the table or bench H is mounted apparatus for impressing the desired amount of energy on the electrodes l8 and W, or controlling the length of time during which the impressed power operates, which apparatus will now be described.

The reference character 55 designates a motor,

or other prime mover operable at substantially uniform speed, connected through reduction gearing 56 to shaft 5'! on which is keyed a clutch element 58 formed with a series of holes or pockets 59. Aligned with the shaft 51, and journalled in suitable brackets 8! and 62, is a shaft 58, on which is keyed a clutch element 84 carrying arms and 66. In the arms 85 and 66 is reciprocably mounted a clutch device 61, with a slightly pointed end portion 58 adapted to fit in any one of the pockets 59 of the clutch 58. The device 81 has a collar 69 between which and the arm 66 acts a compression spring H for urging the member 87 into one of the pockets 59 for clutching engagement with the member 58.

The parts are normally out of clutching en- 1 gagement, however, by virtue of cam lever 12 pivoted to a bracket 18, as indicated by the reference character 14, and normally biased by tension spring 75, so that the end portion 16, comprising a lower beveled or camming portion 11, fits between the arm 85 and the collar 69, as shown most clearly in Figures 1, 2 and 7, and holds the clutch device 67 out of engagement with the member 58. It is only when the relay 53 is energized to raise the cam lever 12 through connecting rod 88, that the clutch device 61 is allowed to reciprocate to the left and engage the clutch member 58.

Such engagement causes the shaft 83 to be operated, from the continuously rotating member 58, for one complete revolution or until the collar 59 rides on the beveled or camming portion ll of the cam lever 72. The lever 32 is merely raised instantaneously and then dropped, thereby withdrawing the pointed end portion 68 from engagement with the pocketed clutch member 58, and allowing the shaft 68 to stop.

The shaft 88 carries a plurality of cam discs 18 and 19, which are adjustably related with respect to one another, as by having one of the discs, as 79, fixed on the shaft 53, while having the other, (or others) as l8, rotatable thereon, but held in adjusted position by connection to an adjusting plate 8i, keyed to the shaft 83 and having an arcuate slot 82 receiving a stud or bolt 85 from the disc 18, adapted to be tightened for holding the disc 18 to the plate 8i in adjusted position.

The cam disc 78 is formed with a high dwell portion 86 and a low dwell portion 85, while the cam disc 79 is formed with a high dwell portion 86 and a low dwell portion 87. Cooperating with the cam disc 18 is a break contact device 88, pivoted at 89, and carrying a contact lug or roller 9!, adapted to traverse the periphery of said disc when rotating, and moving from the high dwell surface 88 to the low dwell surface 85, during which movement the adjustable contact member 92 is withdrawn from engagement with the spring contact member 93 to break an electrical circuit therethrough.

The cam disc 79 is engaged by "make contact device 95, pivoted at 95, and carrying a contact lug or roller 96, which rides back and forth between and on the dwells 86 and 81 thereof. When dropping from the high dwell 88 through the conductor 99, in series with the contacts 92v and 93, as shown most clearly in Figures 5 and 8.

The elements 98, 91, 99, 92 and 93 are in the circuit which connects the primary winding IUI of transformer I92 to the operating lines I83 and [M through main switch I08. Therefore, when the clutch members 80 and [I are engaged and the discs 19. and I! rotated, starting from the position illustrated in Figures 4 and 8, the contact device 94 first drops from the high dwell 88 to the low dwell 81 to cause the contacts -97 and 98 to engage, energizing the transformer I02 and causing the secondary winding lOl' thereof to supply the desired electrical energy to the electrodes it and ill, which at that moment are closed, through the electrical connecting elemerit 60.

lower is supplied until the shaft 53 has rotcted enough to allow the lorecls contact device 88 to drop from the high dwell 83 to the low dwell 55, withdrawing the contact 52 from the contact 93, opening the circuit through the primary winding lot of the transformer E02, and shutting oh the power to the electrodes i3 and ill.

It will therefore be seen that :2, cycle oi opers= tions when using the apparatus of Figmes lto is, inclusive, is that the switches its and 6% ere first closed to start the motor and cause it to run continuously. The treoclle All is then. de= pressed by the operator through the angle iii, bringing the electrodes l3 and ill into eugooe= meet with whet is to he welded thereby, hetween the adjacent end. portions. Further movement of the treetile, or until the cngles 62 and 55 have been traversed, results in momentary energizo= tion of the solenoid 63, by lug 2G riding up on the corn device 35, closing the mercury switch momentarily, and then dropping heel: over the huh and on release of te trecdle, returning under said corn device. The clo mg of the switch causes the necessery encrsisstiou oi the sole noicl end the raising of the corn lever ill, to allow the clutch elements '5? curl to become engaged and cause ems discs :19 V8 to turned. only one complete revolution.

During this complete revolution, the electrodes and B8 are energized for o l gth of time ending on the speed of rotation or" the shalt and the angular displacement leettveeri e contact lever 93 drops oil in high dwell 8E and where the contact lever 88 oh? the high dwell 86.

It will, therefore, he sees that with my apps retus, .i am able to accurately determine the length of time electric current is delivered to electrodes it end it, and. thereby assure that t e welding operation will he uniform, as well as that the application or" energy during one ot er otiori of the tresclle will not he accidentally repeated.

Referring now to the eriieodlrnerit of my inveri= tion illustrated in Figures 9 and ill, there is shown 9. bench or table il on which is mounted a crochet ill sdjustshly supporting the lower electrode '13 of apparatus for welding smell. parts, as in the preceding embodiment,

The table M else carries c. bracket it in which is iourriellecl a shaft it serving to pivot elly mount an arm th filled on sold shaft, and

carrying on upper electrode il ywhich is adapted to cooperate with the electrode it in the performance of welding operations.

The electrode ii! is normally held in its upper position, as illustrated, as by means of e. spring it acting on the reerwsrdly projecting arm ifi of a bell crank so, pivoted with respect to the shaft H and with its lower end connected to the bracket Et A tension spring 39 connects the bell crank arm I9 with an arm 48*, fixed on the shaft Ii,

till

and resiliently urges the bell crank arm 2| against a. stud or lug 42' on an arm 43 fixed on the shaft I5. Thus the electrode I1 is resiliently urged to uppermost position by the spring I! acting on the arm l9 and the arm 2i act= ing on the lug 42 of the arm 43, to urge the shaft l5 and arm l6 carried thereby, in a counter-clockwise direction, as viewed in Figure 9.

A treadle is pivoted to a floor bracket 45", as indicated at 46 and. connected to the arm it by e. chain or the like ll passing over pulley 48* pivotally mounted at te When the operator w depresses the treedle it to the position indicsted by dotted lines W, the electrode ll is brought into engagement with that designated i3. Upon further movement, or when the treedle has moved to the position designated by the reference character it, the mechanism heriesth the table for supplying the requisite omount of electrical energy to said electrodes is insole operative for impressing the desired amount of energy on the electrodes i3 and it, or for controlling length of time which the impressed FOWEE operates, which oopsrstus will now he described.

The reference character designates motor or other tar-"hue mover connected through re cluction scoring 523 to theft Gi jourcelleol in hrocizet till. The end oi the shaft ill remote from reduction gearing I38, carries the mor molly moving tiriviris element lilo o friction clutch Aligned with the strait Elli anti ioumolled in suitable "ii-rockets (li 52 is o W on which o cooperating friction clutch element iii resiliently pressed into onerou tirre eneoserseut with the element E08, by coni= erection coil tit, operating hetween it one. the loreclzet ti carries plurality of com discs it'l d til which are ediustshly reletccl with to one another 21s by having one of the discs, us i 13 fixed on the chef's (53 while having the other (or othersl, es 18 rototshle thereon hut helrl in u'iiusted 3:- es ion by connection to adjusting plate Si keyed to the to, one hot/"ins o-rcucte slot 82 receiving 9. or icoit et from the l8, selected to he tight= erred for holding the disc US to plate ti in erliustecl "position. i

the corn disc iii is formed with at high dwell portion to o low dwell portion Ett while the corn disc U9 iorrned s high dwell cortices it end 10W dwell portion Ol Coco erotics with the cons disc til is at break con= tact device 88 pivoted and carrying e. contact or roller Ell and associated with contacts for moms end loreehirig circuit, such as shown in Figure c for the device 88.

The com disc it is engaged icy e "rs rehe contact device M pivoted, end csiuyiric e contact lug or roller which rides leech and forth loe= tween the dwells 86 and 81 thereof, dropping from the high dwell 86' to the low dwell it, making and breaking o circuit exactly like the contact device 8% in Fisure In the present embodiment the shift 83 carries e. stop her tit, fixed thereto, in adjusted position as by moons of the set screw ill. The outer end portion or the stop bar its is normally engaged and held stationary by the arm H5 or e latch H8, normally urged in c. counter-clockwise direction by spring ill. secured to its arm H8, and with its other end connected to an arm H9 secured to a bracket i2i'.

Rotation of the latch H8 in a counter-clockwise direction beyond its normal position, illus-: trated in full lines in Figure 9, is prevented by a suitable stop on bracket iii. said latch H8 is=engaged by a hooked end 1122 of a connecting roditt, pivoted to and extending from the treadle 4d. Said rod is resiliently heldin place against the latch arm Hit, as by means of a tension spring 82% acting between it and a depending bracket 525. It will, therefore be seen that a depression of the treadle, beyond the point indicated in dotted lines, by the reference character 430', as to the position dd, first releases the stop bar, as by moving the arm M6 from engagement therewith, and allows the shaft The arm MB of asiases will also be understood that although I have shown the illustrated embodiments operated by means of a treadle, manual operation may be substituted, if desired.

I claim: i. A timing device comprising a shaft, a pluruality oi cam means on said shaft, associated continuously running motor, a clutch between (it to makeone complete revolution, whereupon it is stopped by the latch M8, which goes back to normal position under the action of the spring Ml upon the hooked end i222 of the connecting rod E28 passing therebelow. Release of the treadle id and its return to initial or full line position, as shown in Fig. 9, does not again release the stop bar M8, but merely allows the hooked end 522 of the connecting rod i23 to reengage the arm H8, as illustrated.

This release of the stop bar H3 and rotation of the shaft 63 has the same effect in energizing the electrodes ll and it! which have been in contact, as the engagement of the clutch elements 67 and 58 in the preceding embodiment, and thereby effects a welding operating in a similar manner.

Thus a cycle of operations, when using the apparatus of Figures ,9 and 10, is that after closing switches corresponding with those designated m5 and we in Figure 8, to start the motor 55 and cause it to run continuously, the treadle 641 is first depressed by the operator 56 to the position 341 bringing the electrodes ill' and W into engagement with one another, or clamp articles to be welded therebetween.

A further movement of the treadle as to the position 66, results in release of M8, allowing the cam discs it and E9 to be turned one complete revolution, during which the electrodes il and it are energized, as in the preceding embodiment, through a circuit including the electrical connecting element 68, for a length of time depending on the speed of rotation of the shaft 63 and the angular displacement between where the contact lever 943 drops off the high, dwell til and where the contact lever 38 drops off the high dwell 86 It will thus be seen that by use of the present embodiment, I am also able to accurately determine the length of time electric current is delivered to electrodes E3 and ill, and thereby assure that welding or other operations will be uniform, as well as that the application of energy during one operation of the treadle M will not be accidentally repeated, as control of the clutch through the treadle is terminated, either by the dropping of the lug 2d back over the hub of the cam device 34, (Fig. 3), or by the disengagement between the hooked end 522 of the connecting rod I23 and the arm N8 of the latch M8 (Fig. 9), until after return of said treadle to initial position.

Although preferred embodiments of my invention have been illustrated, it will be understood that I do not wish to be limited to the number of cam discs shown, or the use of the apparatus for welding operations, as another or other discs may be provided in order to perform preliminary heating or like operations or other processes. It

the stop bar tion, during said motor and shaft, a pivoted member controling the operation of said clutch, a device movable by an operator to trip said member and make the clutch effective to turn the shaft and elements carried thereby through only a definite angle, and means terminating the control of said; pivoted member through said device, when the clutch is once made efiective by normal movement, until after return of said device to initial position.

2. A timing device comprising a shaft, a plu= rality of' cam means adjustably mounted on said shaft, a make" contact device resiliently urged into engagement with one of said means, a break contact device resiliently urged into engagement with another of said means, a source of electrical energy in series with said cam means and contact devices, means for readily adjusting the relationship between one of said contact devices and its cam means to alter the amount of energy delivered, a continuously running motor, a clutch between said motor and shaft, a pivoted member controlling the operation of said clutch, and a treadle operable to trip said member and then lose control thereof until after return of, said treadle to initial position, and make the clutch effective to cause said shaft and elements carried thereby to make only one revoluwhich the "make contact drops to close an electric circuit until the break contact drops to open said circuit.

3. A timing device comprising a shaft, a pinrality of cam discs adjustably mounted on said shaft, a continuously running motor, a clutch between said motor and shaft, said clutch being normally in disengaged position, a solenoid, a pivoted clutch-release device operable by said solenoid, a device movable by an operator to close a circuit through said solenoid and allow said clutch to engage for turning said shaft and elements carried thereby through only 360, and means terminating the operator's control of said last-mentioned device after one energizatlon of said solenoid until a return of said device to initial position.

4. A timing device comprising a shaft, a plu-. rality of cam discs adjustably mounted on said shaft, a make contact device resiliently urged into engagement contact device resiliently urged into engagement with another of said discs, a continuously running motor, a clutch between said motor and shaft, :2. pivoted device normally holding said clutch from with one of said discs, a break" treadle after only one energizatlon until return or said treadle to initial position.

5. A timing device comprising a shaft, 9. plurality of cam discs and a stop device adjustably mounted on said shaft, a pivoted latch normally engaged by said stop device, a continuously running motor, a clutch between said motor and shaft, and a release device operable to momentarily rotate the latch away from said stop device and allow the shaft and elements carried thereby to make only one revolution, and means then breaking the connection between said release and stop devices until after a return of the former to initial position,

6. A timing device comprising a shaft, a plurality of cam discs and a stop bar adiustably mounted on said shaft, a make contact device resiliently urged into engagement with one of said discs, a break contact device resiliently urged into engagement with another of said discs, at pivoted latch normally engaged by said step bar, a continuously running motor, a clutch between said motor and shaft, a treadle operable to normally rotate the latch away and release said bar, to allow said shaft and elements car ried thereby to make only one revolution, dur ing which the make contact drops close an electric circuit, until the break contact drops to open said circuit, and means then breaking the connection between said treadle and latch until after the former returns to initial position.

7. it. timing device comprising a shaft, a plu= rality of earn discs with high and low dwells adjustable with respect to one another and mounted on said shalt, a make contact device resiliently urged into engagement with one of said disks, a break contact device resiliently urged into engagement with another oi said disks, continuously running motor, a clutch between said motor and shalt, a bevelled carnming de vice normally preventing operation of said clutch, a solenoid operatively connected to said device, a treadle operable to close a circuit through said solenoid to withdraw said camming device and make the clutch effective, to cause said shaft and elements carried thereby to snake only one revolution, during which the make contact drops from its high to its low dwell to close an electric circuit until the break contact drops from its high to its low dwell to open said cir= cult, and means breaking the control or said circuit by said treadle after only one energization until return of said treadle to initial position.

8. A timing device comprising a shaft, a plurality oi cam disks with high and low dwells, and a stop bar adjustable with respect to one another and mounted on said shaft, a make contact device resiliently urged into engagement with one of said disks, a break contact device resiliently urged into engagement with another oi said disks, a pivoted latch normally engaged by said stop bar, a continuously running motor, a friction clutch between said motor and shaft, a treadle operable to rotate the latch away and release said bar, to allow said shaft and elements carried thereby to make only one revolution, during which the make contact drops from its high to its lower dwell to close an electric circuit, until the break contact drops from its high to its low dwell to open said circuit, and means then breaking the connection between said treadle and latch until after the former returns toinitial position.

9. A device for timing the application of elec trical energy during welding operations comprising a pivoted initiating lever, moving cam means and associated contact devices, means for readily adjusting the relationship between one of said contact devices and its cam means to alter the amount of energy delivered, operating means for said lever, and intermediate mechanism causing loss of control of said lever by said operating means after one actuation until return to initial position, whereby said timing means are moved, for performing only one timing cycle dur- I ing each welding engagement.

10. In electric welding apparatus, a pair of electrodes, a timing device therefor, comprising a shaft, a plurality of cam disks with high and low dwells adjustable with respect to one another and mounted on said shaft, a make contact device resiliently urged into engagement with one of said disks, a break contact device resiliently urged into engagement with another of said disks, a continuously running motor, a clutch between said motor and shaft, a bevelled camming de vice normally preventing operation of said clutch, a solenoid operatively connected to said device, a treadle operable to bring the electrodes together and simultaneously close a circuit through said solenoid to withdraw said camming device and make the clutch efiective, to cause said shaft and elements carried thereby to make only one revolution, during which the make contact drops from its high to its low dwell to closean electric circuit through the primary or" a transformer, the secondary or" which is in circuit with said electrodes, until the break contact drops from its high to its low dwell to open said circuit, and means breaking the control of said circuit by said treadle after only one energization until return of said treadle .to initial position.

ll. In electric welding apparatus, a pair oi electrodes, a timing device comprising a shaft, a plurality of cam means with high and. low dwells and a stop bar adjustable with respect to one another and mounted on said shaft, a make contact device resiliently urged into engagement with one of said means, a break contact device resiliently urged into engagement with another of said means, a latch normally engaged by said stop bar, a continuously running motor, a triotion clutch between said motor and shaft, a treadle operable to cause engagement between said electrodes and what is to be welded and simultaneously pull the latch away to release said bar, allowing said shaft and elements carried thereby to make only one revolution, during which the make contact drops from its high to its low dwell to close an electric circuit through the primary oi a transformer, the secondary of which is in circuit with said electrodes, until the break contact drops from its high to its low dwell to open said circuit, means for readily adjusting the relationship between one of said contact devices and its cam means to alter the amount of energy delivered, and means then breaking the connection between said treadle and latch until after the former returns to initial position.

12. A timing device comprising a shaft, cam means mounted on said shaft and provided with high and low dwells, make and break contact devices in series with a source of electrical energy and resiliently urged into engagement with said cam means, means for readily adjust ing the relationship between one of said contact devices and its cam means to alter the amount of energy delivered, a treadle operable to close a circuit from said source and cause rotation of said cam means and electrical current to pass through said make and "break" devices, only during a single period determined by the relative contact and cam setting, from the time the make contact drops from a high to a low dwell until the break" contact drops from a high to a low dwell on said cam means, and means breaking the control of said circuit by said treadle after only one energization until return of said treadle to initial position.

13. A timing device comprising a shaft, cam means mounted thereon, means for causing said cam means to rotate continuously at substantially uniform speed, said cam means having high and low dwells, a "make contact device resiliently urged into engagement with said cam means, a break contact device in series with said make device and resiliently urged into engagement with said cam gageable by said "make device when on a low dwell, a contact engageable with said break device when on a high dwell, a transformer with its primary connected to a source of electrical energy through said contacts, means for readily adjusting the relationship between one of said contact devices and its cam means to alter the amount of energy delivered, a control lever for initiating operation of the device, means to release said lever to start the timing operation, closing a circuit through said contacts as the cam means rotates, to pass current to said primary in series therewith, for a single period of time predetermined by the setting of'the-break device with respect to said cam means, and intermediate means causing loss of control of said lever release means after one actuation until return thereof to initial position.

1%. In electric welding apparatus, a pair of electrodes, and means, including a pivoted lever,

for timing the welding engagement thereof and insuring that only a predetermined quantity of energy is delivered during each operation, comprising moving cam means and associated contact devices for timing the application of electrical energy during welding operations, means for readily adjusting the relationship between one of said contact devices and its cam means to alter the amount of energy delivered, and means-for simultaneously bringing said electrodes together and energizing said means, including operating means for said lever and intermediate mechanism causing loss of control of said lever by said operating means after one actuation until return to initial position, whereby said timing means are moved for performing only one timing cycle during each welding engagement.

15. In electric welding apparatus, a support, an electrode adjustably mounted on said support, a bracket, a shaft journaled therein, an arm fixed on said shaft, a movable electrode carried thereby for cooperating with said adjustably mounted electrode, a bell crank lever pivoted with respect means, a contact ento'said shaft and having forwardly and rearwardly projecting arms, a forwardly projecting arm fixed on said shaft and having a lug projecting into the path of movement of the forwardly projecting arm of said bell crank lever, a rearwardly projecting arm fixed on said shaft, resilient means acting between said rearwardly projecting arm and the rearwardly projecting arm of said bell crank lever for holding said lug and forwardly projecting arm in engagement, means acting on the rearwardly projecting arm of said bell crank lever to hold the electrodev carrying arm in upper position with the movable high and low dwells, and

electrode separated from the adjustably-mounted electrode, switch means pivotally mounted on said bracket and having an operating extension lying in the path of movementof the forwardly projecting arm of said bell crank lever, a treadle, means operatively connecting said treadle and said forwardly projecting arm of said bell crank lever, whereby normal depression of said treadle first brings the movable electrode into engagement with said adjustable electrode, then momentarily closes said switch means, and finally opens 'said switch means, a timing device for the current supplied to said electrodes comprising a shaft, a plurality of cam disks with high and low dwells, adjustably-mounted with respect to one another, on said shaft, a make contact device resiliently urged into engagement with one of said disks, a break contact device resiliently urged-into engagement withanother of said disks, a continuously running motor, a clutch between said motor and shaft, a bevelled camming device normally preventing operation, of said clutch, and a solenoid operatively connected to said device and energizable by a circuit controlled by said switch means so that when said switch means is closed by depression of the treadle, said solenoid withdraws said camming device and makes the clutch effective, whereby the shaft and elements carried thereby make only one revolution, during which the make contactdrops from its high to its low dwell to close an electric circuit to the primary of a transformer, the secondary of which is in circuit with said electrodes, until the "break" contact drops from its high to its low dwell to open said circuit, after the application of a desired amount of energy to said electrodes.

16. In electric welding apparatus, a support, an electrode adjustably mounted on said support, a bracket, a shaft journalled therein, an arm fixed on said shaft, a movable electrode carried thereby for cooperating with said adjustably-rnounted electrode, a bell crank lever pivoted with respect to said shaft and having forwardly and rearwardly projecting arms, a forwardly projecting arm fixed on said shaft and having a lug projecting into the path of movement of the forwardly projecting arm of said bell crank lever, a rearwardly projecting arm fixed on said shaft, resilient means acting between said rearwardly projecting arm and the rearwardly projecting arm of said bell crank lever forholding said lug and forwardly projecting arm in engagement, means acting on the rearwardly projecting arm of said bell crank .lever to hold the electrode-carrying arm in upper position with the movable electrode separated from the adjustably-mounted electrode, a treadle, means operatively connecting said treadle and said forwardly projecting arm of said bell crank lever, whereby normal depression of said treadle first brings the movable electrode into engagement with said adjustable electrode, a timing device for the current supplied to said electrodes comprising a shaft, a plurality of cam disks with a s p bar adjustablymounted with respect to one another on said shaft, a make contact device resiliently urged into engagement with one of said disks, a "break" contact device resiliently urged into engagement with another of said disks. a latch normally engaged by said stop bar, motor, a clutch between said motor and shaft, said treadle being also operable to pull the latch away and release said bar. after engagement bea continuously running tween said electrodes, to allow the shaft and elements carried thereby to make only one revolution, during which the "make contact drops from its high to its low dwell to close an electric circuit to the primary of a transformer, the secondary of which is in circuit with said electrodes. until the break contact drops from its high to its low dwell to open said circuit, after the application of a desired amount of energy to said electrodes.

17. In electric welding apparatus, a support, an electrode adjustably mounted on said support, a bracket, a shaft journalled therein, an arm fixed on said shaft, a movable electrode carried thereby for cooperating with said adjustablymounted electrode, a bell crank lever pivoted with respect to said shaft and having forwardly and rearwardly projecting arms, a forwardly projecting arm fixed on said shaft and having a lug projecting into the path of movement of the forwardly projecting arm of said bell crank lever, a rearwardly projecting arm fixed on said shaft, resilient means acting between said rearwardly projecting arm and the rearwardly projectin arm of said bell crank lever for holding said lug and forwardly projecting arm in engagement, means acting on the rearwardly projecting arm of said bell crank lever to hold the electrodecarrying arm in upper position with the movable electrode separated from the adjustably-mounted electrode, a control device movable by an operator, means operatively connecting said device and the forwardly projecting arm of said bell crank lever, whereby normal depression of said device brings the movable electrode into engagement with the adjustable electrode, a timing device for the current supply to said electrodes comprising a shaft, a plurality of cam disks with high and low dwells adjustably mounted with respect to one another on said shaft, a make contact device resiliently urged into engagement with one of said disks, a break contact device resiliently urged into engagement with another of said disks, a continuously running motor, a normally ineffective clutch between said motor and shaft, said device being also operable, after engagement between said electrodes, to make said clutch effective and cause said shaft and the elements carried thereby to make only one revolution, during which the make contact drops from its high to its low dwell to close an electric circuit to the primary of a transformer, the secondary of which is in circuit with said electrodes, until the break contact drops from its high to its low dwell to open said circuit, after the application of a desired amount of energy to said electrodes.

18. In electric welding apparatus, a support, an electrode adjustably mounted on said support, a bracket, a shaft journalled therein, an arm fixed on said shaft, a movable electrode carried thereby for cooperating with said adjustablymounted electrode, a bell crank lever pivoted with respect to said shaft and having forwardly and rearwardly projecting arms, a forwardly projecting arm fixed on said shaft and having a lug projecting into the path of movement of the forwardly projecting arm of said bell crank 1ever, a rearwardly projecting arm fixed on said shaft, resilient means acting between'said rearwardly projecting arm and the rearwardly projecting arm of said bell crank lever for holding said lug and forwardly projecting arm in engagement, means acting on the rearwardly projecting arm of said bell crank lever to hold the electrode-carrying arm in upper position with the movable electrode separated from the adjustably-mounted electrode, a control device movable by an operator, and means operatively connecting said device and the forwardly projecting arm of said bell crank lever, whereby normal depression of said device brings the movable electrode into engagement with the adjustable electrode.

LANDON RALLS CALVERT. 

